Gaseous fuel internal combustion engines powered with a lean mixture of gaseous fuel and air may comprise a pre-combustion chamber (also referred to as pre-chamber) per cylinder for ignition purposes. Particularly, large-bore engines may benefit from those pre-chambers as it is otherwise difficult to consistently achieve complete and thorough combustion using lean fuel air mixtures.
Typically, such a pre-chamber is fluidly connected to a main combustion chamber of a respective cylinder via a flow transfer passage including a riser channel and a plurality of flow transfer channels. The flow transfer passages allows the flow of the lean mixture of gaseous fuel and air from the main combustion chamber into the pre-chamber during a compression stroke via the flow transfer channels and the riser channel. Enrichment of the lean mixture in the pre-chamber may be effected by providing a small quantity of (gaseous) fuel into the pre-chamber via a separate fuel feed passage, for example during the intake stroke. The enriched mixture is ignited in the pre-chamber by an igniter such as a spark plug. The ignition of the enriched mixture causes a flame front of hot gases that propagates from the pre-chamber via the flow transfer passage into the main combustion chamber. Thus, the lean mixture in the main combustion chamber ignites and burns, and thereby, expands against a movable piston that drives a crankshaft.
For example, US 2013/0160734 A1 discloses a pre-chamber system for an internal combustion engine. The pre-chamber system has a pre-chamber, a fuel introduction device, and a dead space which connects the fuel introduction device to the pre-chamber. A channel is provided which connects the pre-chamber to the dead space so that the dead space can be flushed to avoid rich zones in the dead space and hence the formation of soot particles.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems.